(1) Field of the Invention
The present invention relates to a power system of a washing machine and, more particularly, to a power system of a washing machine which can suppress rotation of the spin basket during a laundering operation and allow the same to rotate at high speeds during a spin drying operation.
(2) Description of the Related Art
Generally, a washing machine includes a main body defining an outer configuration thereof, a water reserving drum or water tub installed within the body, a rotating drum or spin basket, and an agitator blade mounted within the water reserving drum. A power system for driving the rotating drum and blade is mounted under the water reserving drum.
The power system conventionally comprises a motor, a power transmission system, and a belt for connecting the motor to the power transmission system. This will be described hereinbelow with reference to FIG. 6.
As shown in drawing, a conventional power transmission system 100 has a hollow dehydrating shaft 11 and a hollow laundering shaft 102 inserted into the hollow portion of the hollow dehydrating shaft 101. The laundering shaft 102 is divided into upper and lower portions, with a planetary gear unit 103 being disposed therebetween. The planetary gear unit 103 changes a rotating speed of the power transmission system 100. A brake band 14 and a brake lever 105 are disposed beside the dehydrating shaft 101 to brake the rotation of the dehydrating shaft 101. A one-way bearing 106, for suppressing an idling of a rotating drum (spin basket) 110 by cooperating with the brake band 104 and permitting the dehydrating shaft 101 to rotate in only one direction, is mounted on an outer circumference of the dehydrating shaft 101. In addition, a clutch spring 107 and a clutch lever 108 for transmitting/interrupting power from the motor to both the dehydrating shaft 101 and the laundering shaft 102 are mounted under the one-way bearing 106. A pulley 109 on which a belt (not shown) is engaged is mounted on a lower end of the laundering shaft 102.
In this conventional power transmission system 100, torque of the motor is selectively transmitted to a rotating blade 111 or the rotating drum 110 through the clutch spring 107, thereby performing the washing and dehydrating (spin drying) operations. To achieve this, it is necessary that the clutch spring 107 has a high degree of tensile strength to enable the transmission or interruption of torque from the motor to the dehydrating shaft 101 and the laundering shaft 102, both of which are rotated at a high speed. However, the manufacturing process for such a spring having high tensile strength is complicated, and, as a result, manufacturing costs are increased.
In addition, the brake band 104 for preventing the rotating drum 110 from idling during the washing operation is, when it brakes the rotating drum 110 in one direction, subjected to high resistance by a force generated when the rotating drum 110 is being urged to rotate by a water current created within the water reserving drum. The above described one-way bearing 106 must thus be used, making the structure complicated and increasing manufacturing costs. Finally, an unpleasant noise is generated during the braking operation of the brake band.
As described above, the conventional power system of a washing machine is complicated with regard to the arrangement of parts for performing the washing, dehydrating and braking operations, making it difficult to manufacture the same and increasing manufacturing costs. In addition, because of the large number of parts needed for this complicated arrangement, much space is required which, in turn, acts to increase the overall size of the washer.